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991.
Jinting Zhou Wei Lu Fangyu Hu Mengyu Zhang Liming Jiang Zhiquan Shen 《Journal of polymer science. Part A, Polymer chemistry》2014,52(16):2248-2257
A novel AB type of clickable monomer, (S)‐2‐[(2‐azido‐1‐phenylethylimino)methyl]‐5‐propargyloxyphenol (AMPP) was designed and polymerized to yield a class of main‐chain chiral poly(imine‐triazole)s through the metal‐free click reaction. With the thermally induced polymerization, the desired polytriazoles can be easily prepared in high yields by a stepwise heating‐up process and have the number‐average molecular masses ranging from 5.1 × 103 to 58.1 × 103 (polydispersity indices = 1.38?1.68). The polymers were characterized by Fourier Transform Infrared spectroscopy (FTIR), 1H Nuclear Magnetic Resonance (NMR), and gel permeation chromatography, and their optical properties were studied by fluorescence and circular dichroism (CD) spectroscopies. As a chemosensor, these polymers exhibited a selective “turn‐on” fluorescence enhancement response toward Zn2+ ion over other cations such as Na+, K+, Mg2+, Ca2+, Ag+, Pb2+, Cd2+, Hg2+, Mn2+, and Ni2+ in dimethyl sulfoxide. However, the Zn2+‐induced fluorescence signal was subject to serious interference by Al3+, Cu2+, Cr3+, and Fe3+ ions. Interestingly, the chiral polymer showed distinctive changes in the CD spectra on complexation with Zn2+, which allowed for the discrimination of this ion in the presence of other species tested including those interfering ions observed in the fluorescent detection. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2248–2257 相似文献
992.
Wei Sun Xiaojie Li Kazuyuki Hokamoto 《Applied Physics A: Materials Science & Processing》2014,117(4):1941-1946
We show direct evidence that underwater shock wave enables us to bond multithin plates with flat, parallel, and high-strength interfaces, which are key requirements for functionally graded material (also called graded density impactor). This phenomenon is ascribed to the super short duration of the high-speed underwater shock wave, reducing the surface tension, diffusion, evaporation, deposition, and viscous flow of matter. Thin magnesium, aluminum, titanium, copper, and molybdenum foils were welded together and designed with the increase in density. Experimental evidence and numerical simulation show that well bonding between the multilayer structures. Microstructure examinations reveal that the dominant interfacial form shifts from waviness to linearity. Graded density impactor with multilayer structure is proved that can produce quasi-isentropic compression in two-stage gas gun experiment with a designed pressure loading profile, which suggests a feasible method to simulate the conditions we want to study that were previously inaccessible in a precisely controlled laboratory environment. 相似文献
993.
In this paper, the impact of a path selection on other existing paths in optical burst switching (OBS) networks is studied by analyzing the contention among different traffic streams and the interaction between the route selection and traffic load balance. The results show that there exists a mutual reinforcement interaction among the traffic load of a path, the path burst loss ratio and the contention ability of the path when burst loss ratio based multi-path selection strategies are adopted, which may increase the unbalance of traffic and lead to severe congestion further. A maximum-efficiency-first multi-path selection strategy, which considers the performance of the burst flows and the impact of a path selection on existing OBS paths at the same time by a combined metric of route efficiency, is proposed to maximize the utility of the burst flows and minimize the increment of lost throughput on the path. The performance of the proposed multi-path selection strategy is evaluated through simulation. The results show that the presented strategy obviously outperforms the least burst loss ratio strategy and shortest path first strategy in terms of the burst loss ratio in the practical unbalanced background traffic, especially when the network is heavily loaded. 相似文献
994.
995.
Xiao Jun-An Cheng Xiu-Liang Peng Hai Li Jin-Lian Xie Zhen-Zhen Chen Wen-Qiang Liu Zhi-Ping Xiao Qi Su Wei Yang Hua 《中国科学:化学(英文版)》2020,63(6):785-791
A diastereoselectivity-controllable formal [3+2]-cycloaddition of arylvinyl oxirane 2,2-diesters with cyclic N-sulfonyl imines is developed, affording the corresponding tricyclic oxazolidine derivatives in moderate to excellent yields with excellent diastereoselectivities in the presence of palladium(0) or scandium(III) triflate. This protocol allows selective synthesis of diastereomers of tricyclic oxazolidine derivatives under switchable and mild conditions. Further transformations of the obtained products were conducted by removing ester groups and arylvinyl moieties. 相似文献
996.
Wei Hu Xiu-Hua Luo Bao-Lin Xiong Guodong Zhou 《Journal of Pure and Applied Algebra》2019,223(3):1014-1039
We generalize the monomorphism category from quiver (with monomial relations) to arbitrary finite dimensional algebras by a homological definition. Given two finite dimension algebras A and B, we use the special monomorphism category to describe some Gorenstein projective bimodules over the tensor product of A and B. If one of the two algebras is Gorenstein, we give a sufficient and necessary condition for being the category of all Gorenstein projective bimodules. In addition, if both A and B are Gorenstein, we can describe the category of all Gorenstein projective bimodules via filtration categories. Similarly, in this case, we get the same result for infinitely generated Gorenstein projective bimodules. 相似文献
997.
Structures of ionic liquids (ILs) 1-decyl-3-methylimidazolium bis(trifluoromethanesulfonyl)azanide ([C10mim][TFSA]) and 1-decyl-dimethylimidazolium bis(trifluoromethanesulfonyl)azanide ([C10(mim)2](TFSA)2) in different-sized mica slits have been investigated using molecular dynamics simulations. Ion density and angular distributions for monocationic IL [C10mim][TFSA] were analysed to elucidate the IL structures under different surface charges and especially their changes in the direction perpendicular to the surfaces. [C10mim][TFSA] formes in bilayers, compatible with existing models of ILs with long alkyl chains. For dicationic IL [C10(mim)2](TFSA)2, cations adjacent to the mica surface tend to stay parallel to the surface with both positively charged rings absorbed. While near the centre of the slit, dications show the weak tendency of orientation distribution, more random than [C10mim]+ ions. Structures of [C10(mim)2](TFSA)2 cannot be described by bilayer models. Additionally, the in-plane arrangement of [C10mim][TFSA] is more ordered when K+ ions completely neutralise the negative charge of the mica surface, and [C10mim]+ ions tend to be located in hexagonal mica lattices with two aluminium atoms in replacement of silicon atoms. [TFSA]? ions are constrained by the neighbouring K+ ions absorbed onto mica lattices. 相似文献
998.
Chenyang Fan Chonglin Song Gang Lv Jiangjun Wei Xuyang Zhang Yuehan Qiao Ye Liu 《Proceedings of the Combustion Institute》2019,37(4):4821-4829
Post injection has significant benefit in the reduction of diesel soot emissions. Therefore, there is a need to understand the effect of post-injection strategy on soot physicochemical properties and reactivity because they play an important role in soot oxidation process that governs the final soot emissions. This work focuses on the impact of post injection on the physicochemical properties and reactivity of diesel in-cylinder soot using a main plus post injection (M*P) and a single injection (M) strategy. The soot was sampled by a developed total cylinder sampling system, and the dividing points of soot formation-dominant and oxidation-dominant phases were used for studying the impacts of post injection on the characteristics of in-cylinder soot. The physicochemical properties of the soot samples, including primary particle size, nanostructure, carbon chemical state and surface functional groups, were characterized. The soot reactivity was evaluated in terms of peak temperature, burnout temperature and apparent activation energy. In the oxidation-dominant phase, the M*P soot initially possesses smaller primary particle size, shorter fringe length, larger tortuosity, lower sp2/sp3 hybridization ratio of carbon atoms and higher content of aliphatic CH groups than the M soot. The beneficial influence of physicochemical properties on soot reactivity when using post injection is validated by the thermogravimetric data, which shows that the M*P soot is more reactive than the M soot at the onset of the oxidation-dominant phase. In the M*P case, the soot generated from the main-injection combustion has lower reactivity than the soot from the post-injection combustion after they experience the soot formation-dominant phase. The results indicate that the use of post injection leads to in-cylinder soot with physicochemical properties that favor reactivity. The enhancement of reactivity means that the soot will be more readily oxidized in the subsequent combustion process, and consequently contributes to a reduction in final soot emissions. 相似文献
999.
Deep desulfurization by oxidation using an active ionic liquid‐supported Zr metal–organic framework as catalyst 下载免费PDF全文
Jianxiang Wu Yilong Gao Wei Zhang Yueyue Tan Aomin Tang Yong Men Bohejin Tang 《应用有机金属化学》2015,29(2):96-100
In this study, a Zr metal–organic framework (UIO‐66) was synthesized with zirconium tetrachloride and terephthalic acid using the solvent method. Then various masses of 1‐methylimidazolium‐3‐propylsulfonate hydrosulfate (PSMIMHSO4) were supported on the UIO‐66 as catalysts, which were used for catalytic oxidative desulfurization. Sulfur removal using 400 mg of 40% PSMIMHSO4 supported on the UIO‐66 of greater than 94% was obtained at 313 K for 20 min with an O/S molar ratio of 7:1. The results obtained in this work could provide useful information for the design of water‐stable metal–organic frameworks with permanent porosity in applications of catalytic oxidative desulfurization. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
1000.